A woman who slammed her car into a crowd outside a California church, killing four people Wednesday, has been charged with vehicular manslaughter and driving under the influence.

Margo Bronstein, 56, faces five felony charges— four counts of gross vehicular manslaughter, and one  count of driving under the influence of a drug causing injury. The Los Angeles County district attorney's office says she’s expected to be arraigned Friday.

Five children and eight adults, including the suspect and the other driver, suffered injuries including broken bones, abrasions and head trauma in the crash Wednesday night. 

Four people, including a mother and her six-year-old son, later died.

The boy-- Samuel Gaza-- died from his injuries late Thursday at a hospital, Los Angeles County coroner's Lt. David Smith said Friday.

Gaza’s mother, 36-year-old Martha Gaza of Torrance, also died in the incident. Two others, Mary Anne Wilson, 81, and Saeko Matsumura, 87, were also victims of the fatal crash.

A group of pedestrians on Wednesday night had just attended a student Christmas program at St. James Catholic Church in Redondo Bearch when Bronstein sped around the other vehicles in a white Saturn sedan and plowed into the crowd before hitting another car head-on, police Lt. Shawn Freeman said.

Authorities said they believed Bronstein had taken prescription drugs, but were awaiting the results of a toxicology test.

Officials said they do not have information linking her to any prior arrests or DUI-related incidents.

She had a perfect driving record but was restricted to driving a vehicle with hand-controlled brakes, an additional right-side mirror and adequate signaling device, according to Department of Motor Vehicle records.

The DMV had no record listing her as handicapped, however.

Friends and neighbors said she used crutches at times and a motorized wheelchair at longer distances, but they did not know why.

They said she is always friendly and deferential.

"She's very personable, very kind," Vanecia Wiley, a manager at the senior housing community where Bronstein lives, told the Los Angeles Times. "She doesn't want to be in anyone's way."

Dulce Mojarro, 34, met Bronstein two years ago at Disneyland and said the two would sometimes meet up at the park, which Bronstein loved.

"She is like one of those kids that never wanted to grow up," Mojarro told the Times. "I would tell her, 'You have that child in you like Peter Pan.'"

Alan Wells, who lives in the apartment building at the corner, heard the crash and ran outside.

"I saw people lying all over the street, and people in the crosswalk were screaming and yelling," he told the Daily Breeze.

One boy who was struck was flung across the intersection, ending up beneath an SUV's tire, according to witnesses.

"The car is on the little boy. And we finally rolled it off the little boy. He had a little tie on. It was scary. It looked like he was in heaven at that point," Michael Tovar told Fox affiliate KTTV.

The Associated Press contributed to this report.